Riverside Research Institute (RRI) and the Memorial Sloan-Kettering Cancer Center (MSKCC) propose to collaboratively investigate the application of advanced digital ultrasonic tissue characterization (UTC) techniques developed by RRI to detecting, diagnosing and staging prostate cancer and other prostate diseases, and to monitoring and evaluating the effectiveness of prostate-cancer therapies. The proposed research will emphasize application to prostate cancer, the second leading cause of cancer death in American men. RRI and its medical collaborators have shown these computer-based UTC methods to be clinically valuable in diagnosing ocular and abdominal cancers. They currently are being applied to characterizing venous and arterial thrombi. In its initial phase, the proposed research will utilize in-vitro surgical or transurethral-resection specimens to establish a range of potentially useful characterization parameters. Following these initial studies, the research will stress in-vivo studies involving acquisition of ultrasonic radio frequency (rf) data from patients undergoing transrectal ultrasound scanning at MSKCC for known or suspected prostate or bladder disease. Patients subjected to hormonal, radiation, chemotherapeutic and surgical treatments of the prostate will be scanned to establish UTC parameters for planning, monitoring and evaluating protocols. Patients undergoing radical cystectomy, in which the prostate routinely is removed as part of the surgical procedure, will be scanned prior to surgery and used as controls. Ultrasonic results will be correlated with whole-mount pathology specimens whenever possible, including malignant tissue excised in prostatectomies and normal and benign prostate tissue excised in the course of cystectomies. All acquired radio frequency (rf) ultrasonic data will be retained for long-term studies, and all signal-processing results will be entered into a data base along with clinical and histopathological results for statistical analysis. Over the proposed five-year research period, the very large patient population of the Urology Service at MSKCC will provide ample data to assure statistical confidence. RRI will serve as the primary grantee, and the efforts at MSKCC will be supported through a sub-contract with RRI.